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Article
Prediction-Based Path Planning with Obstacle Avoidance in Dynamic Target Environment

Authors: Zahraa Y. Ibrahim --- Abdulmuttalib T. Rashid --- Ali F. Marhoon علي فاضل مرهون
Journal: Basrah Journal for Engineering Science مجلة البصرة للعلوم الهندسية ISSN: Print: 18146120; Online: 23118385 Year: 2016 Volume: 16 Issue: 2 Pages: 48-60
Publisher: Basrah University جامعة البصرة

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Abstract

In this paper, a new algorithm for mobile robot navigation and polygonal obstacles avoidance in dynamic target environment is introduced. In the dynamic target path planning theagent (robot) trying to reach a moving target in minimum pathcost. The introduced algorithm which called Prediction-basedpath planning with obstacle avoidance in dynamic target environment planning a path to a moving target by predicting the nexttarget location, then computing a path from the robot current location to the predicted target location representing each visibleobstacle by the smallest circle that enclosing the polygon obstacle,then determine the visible tangents between the robot and the circular obstacle that intersect its shortest path and compute theshortest path. Three target movement scenarios were suggestedand tested in different environment conditions. The results showthat the target was reached in all scenarios and under all environment conditions with good path cost.


Article
Frequency and Wavelength Dependences of the Electro-optic Coefficients r63 and r41 in Congruent KDP Crystals
اعتماد التردد والطول الموجي للمعاملات الكهروضوئية r63 و r41 لبلورات KDP

Authors: Maha A. Rahma مها عبد الحسين رحمة --- Haitham L. Saadon هيثم لفتة سعدون --- Ali F. Marhoon علي فاضل مرهون
Journal: Iraqi Journal of Laser المجلة العراقية لليزر ISSN: 18121195 Year: 2013 Volume: 12 Issue: A Pages: 7-13
Publisher: Baghdad University جامعة بغداد

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Abstract

Abstract : The electro-optic coefficient r63 and r41 are determined in congruent KDP crystals, using an experimental method based upon the direct measurement of material. Sénarmont system for electro-optic coefficient measurement and characterization of crystals was modified. This modification allowed us to obtain on the frequency dispersion dependence of the electro-optic coefficients within a frequency range up to 20 MHz and on a new version of modulation depth method. To the best of our knowledge, by using this system, the electro-optic coefficients r63 and r41 in different configurations (transverse and longitudinal) have been measured for the first time within a frequency range up to 20 MHz. The measurements have been investigated as a function of laser wavelength ranging from 532 nm to 750 nm. While previously these coefficients where measured at only one wavelength, 632.8 nm, and the unclamped coefficient r63 is known at just 3390 nm. From these measurements, the clamped and unclamped electro-optic coefficients as well as the acoustic contribution have been determined.

الخلاصة: تم تحديد المعاملات الكهروضوئية r63 و r41 لبلورات KDP المتطابقة باستخدام طريقة عملية اعتمدت بالأساس على القياس المباشر للمادة. فقد تم تطوير منظومة سينارمونت لدراسة الخصائص الكهروضوئية والضوئية-الحرارية للبلورات. هذا التطوير سمح لنا بالحصول على الاعتماد الترددي للمعاملات الكهروضوئية ضمن مدى تردد يصل إلى 20 MHz وعلى نسخة جديدة من طريقة عمق التضمين. باستخدام هذا النظام, فإن المعاملات الكهروضوئية r63 و r41 بترتيبات مختلفة (مستعرض وطولي) قيست لأول مرة حسب معرفتنا ضمن مدى تردد يصل إلى 20 MHz. أجريت القياسات كدالّة لطول موجة الليزر من 532 nm إلى 750 nm . بينما هذه المعاملات كانت معروفة سابقا عند طول موجي واحد وهو 632.8 nm , بينما المعامل r63 غير الملزم فهو معروف عند 3390 nm فقط. ومن خلال هذه القياسات تم إيجاد المعاملات الكهروضوئية الملزمة وغير الملزمة وكذلك التوزيع الصوتي.

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